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Wednesday, 28 September 2011

The suggestion in an article in the British Journal of Psychiatry by researcher Priscilla K. Coleman that abortion causes mental health problems now seems to be rapidly falling apart. I voiced some doubts about the quality of Coleman's meta-analysis when posting about her article a while back, and it now seems that exactly the sort of basic faults that I worried about are present in Coleman's analysis. But it doesn't stop there. Two responses to Coleman's paper, both published in the BJoP, point out a number of rather grave deficiencies, and one may seriously wonder when the journal editor will start to think retraction. One may also wonder about the integrity and quality of the peer review process leading up to the publication of Coleman's article. Here are a few snippets of what the critics say:

Huge numbers of papers by respectable researchers that have not found negative mental health consequences are ignored without comment. Not surprisingly, over 50% of the "acceptable" studies she uses as her "evidence" are those done by her and her colleagues Cougle and Reardon. The work of this group has been soundly critiqued not just by us (1, 2) but by many others as being logically inconsistent and substantially inflated by faulty methodologies. As noted by the Royal Society of Obstetricians and Gynaecologists (3), the authors consistently fail to differentiate between an association and a causal relationship and repeatedly fail to control for pre-existing mental health problems. We note that she did not include in her articles the publication by Munk-Olsen et al. in the Jan. 2011 New England Journal of Medicine (4) that concluded that "the rates of a first-time psychiatric contact before and after a first-trimester induced abortion are similar. This finding does not support the hypothesis that there is an overall increased risk of mental disorders after first-trimester induced abortion". (Gail Erlick Robinson MD, DPsych, FRCP Professor of Psychiatry and Obstetrics/Gynaecology University of Toronto
Nada L. Stotland MD, MPH Professor of Psychiatry and Obstetrics/ Gynaecology Rush Medical College
Carol C. Nadelson MD Professor of Psychiatry Harvard Medical School)

This quantitative synthesis and meta-analysis did not follow the robust methodologies now generally accepted for systematic reviews[1]. There is no detail of the search strategy including search terms; the strategy is not comprehensive (only two databases included); other strategies to search the literature including citation tracking, hand searching and contacting authors and experts in the field to try to minimise publication bias were not carried out; and there was no assessment or rating of the quality of included studies, so that only those of at least reasonable quality are included in the meta-analysis. This is particularly important here as many of the primary studies included in this review have significant methodological limitations, including non-prospective design, non-standardised measures of mental disorders, lack of adjustment for pre-existing mental illness, lack of adjustment for other key confounders (e.g. social deprivation), non-comparability of exposed and non-exposed groups, and selection bias. [...]

Finally, the synthesis of the data and the summary statistics are flawed. The criteria for synthesizing data meant that several effect measures were included from the same study. Eleven of the included studies contributed more than one effect measure, with two studies contributing four measures each. Despite the clustering of effect measures by study, they are analysed as independent measures. This is an important limitation, since the use of several effect measures from a flawed study can magnify the bias.

Most importantly for readers of this study to know, is the erroneous conclusions drawn by the author regarding the Population Attributable Risk (PAR). The underlying assumptions for estimating PAR include that there is a causal relationship between the risk factor (abortion) and the disease (mental health) and that there is independence of the considered risk factor from other factors that influence disease risk[8]. These assumptions are clearly not met in this review and therefore it is completely inappropriate to calculate a PAR from these data. (Louise M Howard*, Hind Khalifeh*, Melissa Rowe*, Kylee Trevillion*, Trine Munk-Olsen†,
* Section of Women’s Mental Health, PO31, Institute of Psychiatry, King’s College London †National Center for Register-Based Research, Aarhus University, Aarhus, Denmark)

The first of these critics also point out:

Reardon, the leader of this group, has clearly expressed his new rhetorical strategy as "we can convince many of those who do not see abortion to be a "serious moral evil" that they should support anti-abortion policies that protect women and reduce abortion rates" (5) . He has stated that "I do argue that because abortion is evil, we can expect, and can even know, that it will harm those who participate in it. Nothing good comes from evil." (6). These authors have a clear agenda and publish a steady stream of papers, based on faulty methodology, designed to prove their point. If we and other researchers know this, how is it that reviewers for esteemed journals such as yours consistently fail to recognize these deficiencies and biases?

In short: Coleman and her group has an established track record of faulty, sub-standard and biased research. The article in question has applied faulty methodology on several counts, some of which is so obvious that even a happy amateur like myself could spot it. So, dear editor of BJoP, how come that this article could sneak through the peer review process? How was peer reviewers selected, for example?